1. Field of the Invention
The present invention relates to a fuming, hot-vaporizing insecticide for killing flies, which contains as the active ingredient, propargylfurylmethyl 2,2,3,3-tetramethylcyclopropanecarboxylate of the general formula I: ##STR2## wherein R is hydrogen or methyl, and to a method for killing flies with the insecticide.
2. Prior Art
As insecticides for repelling and exterminating imaginal mosquitoes, popularly used are fuming, hot-vaporizing insecticides in the form of mosquitoes-repellent coils, electric mosquitoes-repellent mats and electric mosquitoes-repellent liquids. In these days, the breeding of mosquitoes is decreasing but there is still a great demand for such mosquito repellents. As the active ingredients in them, widely used are chrysanthemates, for example (.+-.)-2-allyl-3-methyl-cyclopent-2-en-1-on-4-yl (+)-cis, trans-chrysanthemate (hereinafter referred to as pynaminforte), its stereoisomers such as esbiothrin and esbiol, (+)-2-propargyl-3-methyl-cyclopent-2-en-1-on-4-yl, (+)-cis,trans-chrysanthemate (hereinafter referred to as etoc), or 5-propargyl-2-furylmethyl (+)-cis, trans-chrysanthemate (hereinafter referred to as furamethrinforte).
On the other hand, some local areas such as fishing villages, factories for processing fishes and shellfishes, plants for garbage disposal, stock farming houses, chicken houses and around them are often troubled by flies more than before, though the breeding of flies is decreasing in urban areas. As the means for eradicating the sources of breeding flies, various insecticides such as emulsions, oils and powder preparations are used. In addition, space aerosols for repelling and exterminating imaginal flies are popular for domestic use, but these have a drawback that the effect thereof is often transitory and does not last long. Given the situations, a demand for space treating agents of fuming, hot-vaporizing insecticides (fuming coils, mats and liquids), of which the effect lasts for several hours or more, has become increased.
Of these, mosquitoes-repellent coils may be lighted from a match to fume in a broad space and last long, while the effect thereof is kept constant until they are burnt out. Therefore, the means of using them is an extremely reasonable insecticidal method. During its use, a mosquitoes-repellent coil releases its active ingredients therefrom at its part which is remote from the fired part thereof heated at about 800.degree. C. by several mm and which has been heated at abut 200.degree. to 250.degree. C. The diffusibility of the released active ingredients is good since the smoke from the fired mosquitoes-repellent coil acts as a carrier, so that the coil displays a high insecticidal effect even in an open space. On the other hand, regarding mat-type or liquid-type mosquito repellents, the temperature of the heater (a hot plate in the mat-type or a metal ring in the liquid-type) in the heating and vaporizing device fitted in them is from 160.degree. to 180.degree. C. in the mat-type and from 120.degree. to 140.degree. C. in the liquid-type, and is lower than the temperature at the part of the coil from which its active ingredients vaporize, so that the power thereof for vaporizing their active ingredients is somewhat poor. However, these types of mosquito repellents are suitable for use in closed rooms or in the areas where smoke is not accepted.
First of all, in the process of developping a fuming, hot-vaporizing insecticide for killing flies in the form of coil, the present inventor tried to use the above-mentioned chrysanthemates that have heretofore been used in mosquitoes-repellent coil, mats and the like. However, since the effect of pynaminforte or etoc for flies was weak, it was not able to obtain a sufficient insecticidal effect even though the concentration of the active ingredient in the insecticidal preparation was increased. On the other hand, a mosquitoes-repellent coil containing furamethrinforte was shown to be effective, but needed to increase further its insecticidal effect. In addition it was disadvantageous in point of its cost. Also, in a fuming, hot-vaporizing insecticide of mat-type or liquid-type for killing flies, pynaminforte and etoc were ineffective even at high concentration, though furamethrinforte was effective at high concentration. Apart from this, the present inventor selected empenthrin which has the highest vapor pressure among commercial pyrethroids, as the active ingredient, and has already succeeded in developing a flies-repellent coil containing it. However, the coil is disadvantageous in point of its cost. In addition, since the compound vaporizes too much, a significant loss of the compound is inevitable during the drying step in producing coils containing it. In view of these facts, the flies-repellent coil was not always satisfactory. Therefore, the selection of the active ingredient which is most suitable for a fuming, hot-vaporizing insecticide for killing flies was an important theme.
Accordingly, the object of the present invention is to select an active ingredient which is most suitable for a fuming, hot-vaporizing insecticide to be used for killing flies in the form of a coil, mat or liquid and to provide a fuming, hot-vaporizing insecticide for killing flies which is excellent in all the points of insecticidal power, safety, easiness in use and producibility as well as a method of killing flies with the insecticide.
In order to solve the above-mentioned problems in the prior art, the present inventor tested fuming, hot-vaporizing insecticides containing 2,2,3,3-tetramethylcyclopropanecarboxylic acid derivative of furamethrinforte which was shown to be effective in the preceding test, the derivative hereinafter being referred to as tefuramethrin, and he admitted that tefuramethrin had a high flies-killing effect, specifically considering the fact that the vapor pressure of 2,2,3,3-tetramethylcyclopropanecarboxylates are higher than one of the corresponding chrysanthemate, and that the insecticidal activity of the former may be increased when the former is used in the form of a fuming, hot-vaporizing insecticide. The present inventor further has made an extensive scope of research, and finds that propargyl furylmethyl 2,2,3,3-tetramethylcyclopropanecarboxylate of the general formula I is specifically effective. On the basis of these findings, the inventor has completed the present invention.
That is to say, ester of (+)-2-propargyl-3-methyl-cyclopent-2-en-1-on-4-yl or 4-propargylbenzyl alcohol, which is 2,2,3,3-tetramethylcyclopropanecarboxylate has a low flies-killing effect. Therefore, now it is clear that a fuming, hot-vaporizing insecticides with a high flies-killing effect is able to be obtained by a combination of propargylfurylmethyl alcohol and 2,2,3,3-tetramethylcyclopropanecarboxylic acid.